The Dwarka-Barakhamba Road section of the line was inaugurated by the Prime Minister of India, Dr. Manmohan Singh on 31 December 2005 and opened to the public on 31 December 2005. It is the longest line currently running on the Delhi Metro network.

Karkardooma station on Anand Vihar branch is the highest station of Delhi metro with a platform height of 19 metres (62 feet 4 inches). Rajouri Garden station on the main line is the second highest station with a height of 17 metres (55 feet 9 inches).[5]

A branch line from Dwarka station to Najafgarh is planned under Phase III and has received approval. The extension will see 3 new stations being added to the blue line. Construction work on this extension started in September 2013.[9]

In April 2014 the Delhi Government approved the extension of line eastwards from Noida City Centre to Sec-62. The extended line would have 5 new stations in a distance of 6 kilometres (3.7 miles). Later, the Govt. approved the line to be extended till Greater Noida.[10]

A small extension is made from Vaishali to Mohan Nagar of Redline and further extension of the blue line from Noida Electronic city to Sahibabad is being planned. Main Blue line will join branch blue line at Sahibabad.